The present invention relates to apparatus for measuring the contact force between a receptacle contact and a pin.
U.S. Pat. No. 4,380,171 discloses apparatus for measuring the contact force between a resilient contact in a card edge connector and a pad on a printed circuit board received therein. A blade-like probe having a base and a distal end and of like thickness as the printed circuit board comprises two members defining a central space therebetween, one of the members having a pair of parallel slots defining a fixed end beam adjacent the space. The beam has a pair of strain gages bonded thereto toward opposed ends, the gages being connected by leads which further extend into the base for connection to current supply means and galvanometer means remote from the probe. The circuit forms a balanced bridge when the beam is not loaded, an unbalanced bridge resulting when the probe is inserted in a card edge connector and the beam is loaded by the resilient contact. The contact force may thus be determined by well known principles as outlined in Perry, C. C., The Strain Gage Primer (McGraw-Hill, 1962) at pp. 55-73.
The above described strain transducer introduces the fixed beam principle which enables non-destructive testing of contacts in a card edge connector, but cannot readily be adapted for receptacle contacts which receive 0.025 in. square posts. Such contacts, marketed by AMP Incorporated in its AMPMODU connector line, are disclosed in U.S. Pat. No. 4,343,085. It would accordingly be desirable to have a measuring device with a probe profiled as a pin or the like, particularly a 0.025 in. square post.